/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:		arm_abs_q7.c
*
* Description:	Q7 vector absolute value.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
*
* Version 0.0.7  2010/06/10
*    Misra-C changes done
* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupMath
 */

/**
 * @addtogroup BasicAbs
 * @{
 */

/**
 * @brief Q7 vector absolute value.
 * @param[in]       *pSrc points to the input buffer
 * @param[out]      *pDst points to the output buffer
 * @param[in]       blockSize number of samples in each vector
 * @return none.
 *
 * \par Conditions for optimum performance
 *  Input and output buffers should be aligned by 32-bit
 *
 *
 * <b>Scaling and Overflow Behavior:</b>
 * \par
 * The function uses saturating arithmetic.
 * The Q7 value -1 (0x80) will be saturated to the maximum allowable positive value 0x7F.
 */

void arm_abs_q7(
    q7_t* pSrc,
    q7_t* pDst,
    uint32_t blockSize)
{
	uint32_t blkCnt;                               /* loop counter */
	q7_t in;                                       /* Input value1 */

#ifndef ARM_MATH_CM0

	/* Run the below code for Cortex-M4 and Cortex-M3 */
	q31_t in1, in2, in3, in4;                      /* temporary input variables */
	q31_t out1, out2, out3, out4;                  /* temporary output variables */

	/*loop Unrolling */
	blkCnt = blockSize >> 2u;

	/* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
	 ** a second loop below computes the remaining 1 to 3 samples. */
	while(blkCnt > 0u) {
		/* C = |A| */
		/* Read inputs */
		in1 = (q31_t) * pSrc;
		in2 = (q31_t) * (pSrc + 1);
		in3 = (q31_t) * (pSrc + 2);

		/* find absolute value */
		out1 = (in1 > 0) ? in1 : __QSUB8(0, in1);

		/* read input */
		in4 = (q31_t) * (pSrc + 3);

		/* find absolute value */
		out2 = (in2 > 0) ? in2 : __QSUB8(0, in2);

		/* store result to destination */
		*pDst = (q7_t) out1;

		/* find absolute value */
		out3 = (in3 > 0) ? in3 : __QSUB8(0, in3);

		/* find absolute value */
		out4 = (in4 > 0) ? in4 : __QSUB8(0, in4);

		/* store result to destination */
		*(pDst + 1) = (q7_t) out2;

		/* store result to destination */
		*(pDst + 2) = (q7_t) out3;

		/* store result to destination */
		*(pDst + 3) = (q7_t) out4;

		/* update pointers to process next samples */
		pSrc += 4u;
		pDst += 4u;

		/* Decrement the loop counter */
		blkCnt--;
	}

	/* If the blockSize is not a multiple of 4, compute any remaining output samples here.
	 ** No loop unrolling is used. */
	blkCnt = blockSize % 0x4u;
#else

	/* Run the below code for Cortex-M0 */
	blkCnt = blockSize;

#endif //      #define ARM_MATH_CM0

	while(blkCnt > 0u) {
		/* C = |A| */
		/* Read the input */
		in = *pSrc++;

		/* Store the Absolute result in the destination buffer */
		*pDst++ = (in > 0) ? in : ((in == (q7_t) 0x80) ? 0x7f : -in);

		/* Decrement the loop counter */
		blkCnt--;
	}
}

/**
 * @} end of BasicAbs group
 */
